According to Ref. [1]}, the general form of the inter-layer hopping can be written as
\(t_{inter}(r) = & V_0(r) + V_3(r) \left( \cos (3\theta _{12}) + \cos (3\theta _{21}) \right) + V_6(r)\left( \cos (6\theta _{12}) + \cos (6\theta _{21})\right)  \\V(r) = & \lambda _0 e^{- \xi _0 \bar{r}^2} \cos (\kappa _0 \bar{r}) \\V_3(r) = & \lambda _3 \bar{r}^2 e^{- \xi _3 (\bar{r} - x_3)^2} \\V_6(r) = & \lambda _6 e^{- \xi _6 (\bar{r} - x_3)^2}\sin (\kappa _6 \bar{r})\) 
